What may increase the risk of collision with large vessels?

Reduced visibility conditions can significantly increase the risk of collision with large vessels because they impair a boater's ability to see and be seen. In situations where fog, rain, or other obstructions limit visibility, smaller vessels may not be able to detect the presence or movement of larger vessels until it’s too late. Larger vessels, on the other hand, have more blind spots and can be less maneuverable due to their size. This lack of visibility can lead to misjudgments about distance and speed, increasing the likelihood of an accident.

The other choices involve situations that either promote safety—such as maintaining a proper lookout or approaching at slow speeds—or are related to more confined waterways, like operating in a closed harbor, where the risk of collision may be reduced. However, none directly address the element of visibility that can critically impact navigation and safety on the water.